The present invention relates to coaxial connectors and more particularly to such a connector which will accommodate differential expansion between inner and outer tubular conductors in a multi-section run of coaxial transmission line.
As is understood by those skilled in the art, high power coaxial transmission lines are subject to differential expansion between the inner and outer conductors, due mainly to heating of the inner conductor by the r.f. power being transmitted. Typically, this differential expansion is dealt with in either of two ways. One expedient is to provide convolutions or corrugations in either the inner or outer conductor so that some axial compliance is available to take up the differential expansion. Another expedient is to provide an axial sliding joint for one of the inner conductors at each junction between coaxial sections. One problem with this latter technique, as practiced heretofore, however, has been that the sliding joint presented a variable impedance discontinuity which was difficult to compensate for. Further, the prior art expansion systems often exhibited inconsistent electrical conductivity characteristics and utilized metal to metal alignment contacts which could generate metal particles as a result of the rubbing action.
Among the several objects of the present invention may be noted the provision of a novel connector for sections of coaxial transmission line which accommodates differential expansion between the inner and outer conductors; the provision of such a connector which minimizes changes in impedance, particularly those which occur with such differential expansion; the provision of such a connector which provides a well defined point of electrical contact between the connector and the inner conductor; the provision of such a connector which reduces the generation of metal particles by sliding action; and the provision of such apparatus which is highly reliable and is of relatively simple and inexpensive constructions. Other objects and features will be, in part, apparent and, in part, pointed out hereinafter.